Calls all the time.

The caller said that they represented my Health Insurance Co - AARP Complete Medicare through United Health Care.  They wanted me to set up an appointment for me to talk to a representative about the care I was receiving from my doctor - they said it wasn't to replace my doctor but just to make sure that I was receiving the care I was entitled to with my plan.  I told them that I was away and to call back after mid December.  They continued to call my phone for 2 weeks which I refused to answer.  Since being back home I have not received another call from this number.  However, I did receive them from 443-853-3833 and 866-465-1021 with a similar situation only it was concerning my medication and I was to talk to a pharmicist when they called today.  I was not home to receive the call but there were 2 missed calls from the second number listed.  I called United Health Care today and was told that they do not have any representatives making these types of calls.  My instincts tell me that this is some kind of fraud.

This is a call from United Health Care Optum division.  They are checking with customers to make sure you are receiving their screenings, etc.  I did not answer the call then called them back.  They answered and explained who they were and the lady named Doris was very polite and answered any questions I had.
Not fraud, it is ligit.

Same story as above.  After they asked questions, about which United Health would have known the answer, I said I was not going to give out anymore info and hung up.

We, too, got calls from this number. The message left asked us to call Optim at 855-575-0410. When I called the 218 number back, I got a recording thanking me for calling Optim Health, a representative of our United Healthcare Advantage plan. They do surveys and quality control for United. My guess is that most of the United customer service reps are not aware of Optim's existence. Optim is on the web and is a genuine company providing healthcare monitoring services, making sure the Plan doctors and pharmacies are providing good enough service to be United providers. No biggie if you don't call 'em back, but they ARE persistent. Annoyingly so.